JPH11216639A - Lubricating device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress biting, fretting, etc., in order to protect a connection surface of a spindle and a tool holder, improve work accuracy, and prevent a trouble of ATC damage or the like. SOLUTION: Air blow passage 12 is provided leading to a tool holder mounting part 11 of a spindle 1, and a base end of the air blow passage 12 is connected to a compressed air supply source 13. In the halfway of the air blow passage 12, a mixer 14 is arranged, a lubricant accumulating tank 15 is connected to the mixer 14. When a tool is replaced, lubricant mixing air is guided in the tool holder mounting part 11 through the air blow passage 12, a connection surface of a tapered hole 4 and tapered shank 6 is lubricated by a lubricant in compressed air. The mixer 14 is controlled by a controller 19, in accordance with a work condition and a load condition of an ATC3, mixing ratio of the lubricant is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for lubricating a joining surface between a spindle and a tool holder in a machine tool.

[0002]

2. Description of the Related Art In the case of a machine tool in which a tool holder is mounted at the tip of a spindle, the taper shank of the tool holder bites into a tapered hole of the spindle and fretting does not occur due to vibration or impact during machining. Or the joint surface of the spindle and the holder is easily damaged by such a phenomenon, and as a result, the processing accuracy is reduced, and the ATC
(Automatic tool changer) There are problems such as troubles such as breakage occurring. However, in conventional machine tools, measures have been taken to protect the joint surface from foreign substances such as chips, but effective measures have been taken to protect the joint surface from machine-specific phenomena such as biting and fretting. I didn't get it.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent biting and fretting, etc., to protect the joint surface between the spindle and the tool holder, thereby improving machining accuracy, and ATC breakage. It is an object of the present invention to provide a lubricating device for a machine tool which can prevent the above trouble.

[0004]

In order to solve the above-mentioned problems, a lubricating apparatus according to the present invention is provided in a machine tool having an automatic tool changer for attaching and detaching a tool holder to and from a main shaft. A tank for storing lubricant, a mixer for mixing the lubricant with the compressed air, and a passage for guiding the lubricant-mixed air to the tool holder mounting portion of the spindle are provided. The joint surface of the tool holder is lubricated (claim 1).

Here, in order to efficiently lubricate the joint surface between the main shaft and the holder, it is preferable to provide a means for changing the mixing ratio of the lubricant according to the load at the time of processing.
Further, means for changing the mixing ratio of the lubricant according to the load of the tool changing device may be provided. Further, a solid lubricant or a solid release material in the form of powder or fine particles can be used as the lubricant (claim 4).

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In the machine tool shown in FIG.
A tool holder 2 is attached to and detached from the spindle 1 by the ATC 3.
A tapered hole 4 is formed at the tip of the main shaft 1, and a clamp mechanism 5 including a disc spring and the like is provided above the tapered hole 4. The tool holder 2 has a tapered shank 6 fitted into the tapered hole 4.
And a pull stud 7 that engages with the clamp mechanism 5. The ATC 3 includes an exchange arm 8 and an arm drive motor 9.

The main shaft 1 is provided with an air blow passage 12 extending to a tool holder mounting portion 11, and its base end is connected to a compressed air supply source 13. A mixer 14 is provided in the middle of the air blow passage 12, and a tank 15 for storing a lubricant is connected to the mixer 14. And the mixer 14
The compressed air and the lubricant are mixed by the air blow passage 12 when the tool is changed by the ATC 3.
Through to the tool holder mounting portion 11 to lubricate the joint surface between the tapered hole 4 and the tapered shank 6 with the lubricant in the compressed air. As the lubricant, a powdery or particulate solid lubricant or a liquid lubricant such as a ceramic material, for example, a boron nitride-based material having excellent lubricity, or a powder or particulate solid release agent can be used. Alternatively, a liquid release agent can be used.

On the other hand, a machine tool control unit 17 analyzes a machining program to determine a machining condition, and controls a mixer 14 to change a mixing ratio of a lubricant according to the machining condition. A control unit 19 is provided. During heavy cutting such as drilling, the mixing ratio of the lubricant is changed to a value larger than usual, and a large amount of lubricant is supplied to the holder mounting portion 11 to reliably suppress the occurrence of biting and fretting. Further, at the time of light cutting such as finishing, the ratio of the lubricant is changed to a smaller value than usual, so that the holder mounting portion 11 can be efficiently lubricated with a small amount of the lubricant.

Further, the control device 17 includes a load detecting section 20 for detecting an actual load of the arm driving motor 9 in the ATC 3, and a load storing section 2 for storing a standard load of the motor 9.
1 and a load determining unit 22 for comparing the actual load and the standard load to determine the load state of the motor 9. The control unit 19 controls the mixer 1 according to the load condition of the motor 9.
4 is feedback-controlled to change the mixture ratio of the lubricant to a value larger than usual when the actual load> the standard load. Change to a value. Therefore, the holder mounting part 1 is always
By supplying an appropriate amount of lubricant to the ATC 3, the ATC 3 can be operated under ideal conditions of actual load = standard load.

It is to be noted that a learning function is provided to the control unit 19 so that the mixture ratio of the lubricant is rewritably stored in the memory, and the previous mixture ratio data is used as a reference value or a comparison value for the next tool change. Is also good. Further, the technology disclosed in the above embodiment is applied to a system for lubricating a sliding surface of a rotating shaft in a machine tool, and the sliding surface is protected with a lubricant having a mixing ratio according to a surface pressure, a rotation speed, and the like. You may comprise. In addition, the present invention is not limited to the above-described embodiment, and may be embodied by appropriately changing the shape and configuration of each part without departing from the spirit of the present invention.

[0011]

As described in detail above, according to the lubricating apparatus of the present invention, the lubricating surface of the main shaft and the tool holder is lubricated with the lubricant in the compressed air. It is possible to protect the surface, thereby improving the processing accuracy, and prevent the trouble such as ATC breakage.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a lubricating device showing one embodiment of the present invention.

[Explanation of symbols]

1. Spindle, 2. Tool holder, 3. ATC, 4.
Taper hole, 5 clamp mechanism, 6 taper shank, 8 exchange arm, 9 arm drive motor, 11
..Tool holder mounting portion, 12 ... Air blow passage, 13
..Compressed air supply source, 14.Mixer, 15.Tank, 17.Control device, 18.Cutting condition judgment unit, 19
..The control unit, 22..the load determination unit.

Claims (4)

[Claims] 1. A machine tool provided with an automatic tool changer for attaching and detaching a tool holder to and from a main spindle, a supply source of compressed air, a tank for storing lubricant, a mixer for mixing lubricant with compressed air, A lubricating device comprising: a passage for guiding lubricant-mixed air to a tool holder mounting portion of the main shaft; and lubricating a joint surface between the main shaft and the tool holder with a lubricant in compressed air at the time of tool change. 2. A lubricating device for a machine tool according to claim 1, further comprising means for changing a mixing ratio of the lubricant according to a load during processing. 3. The lubricating device for a machine tool according to claim 1, further comprising means for changing a mixing ratio of the lubricant according to a load of the tool changing device. 4. The lubricating device for a machine tool according to claim 1, wherein a solid lubricant or a solid release material in the form of powder or fine particles is used as the lubricant.